How River Bend Geometry Alters Flow Velocity

At a river bend, velocity redistributes dramatically:

• Outside bank (cut bank): Centrifugal force pushes water outward, increasing velocity and depth. Erosion dominates, forming steep, undercut banks.
• Inside bank (point bar): Velocity decreases; sediment deposits, building shallow, sloping point bars.
• Cross-section: Asymmetric—deep outer channel, shallow inner shelf.
• Secondary flow: Helical motion moves surface water outward, bottom water inward.
• Gradient & friction: Steeper slope and lower friction on outside amplify speed.

These dynamics create diverse habitats: deep pools for fish, wetlands on point bars.